Anti-frosting refrigerator

ABSTRACT

A refrigerator with a storage chamber, an evaporation chamber, and a fan for driving an air circulation from the evaporation chamber to the storage chamber. In an exemplary embodiment, the refrigerator may include a grid disposed to cross an elongated inlet opening of the storage chamber.

The present invention relates to a refrigerator with a storage chamber, an evaporation chamber separate from the storage chamber and a fan for driving an air circulation between the evaporation chamber and the storage chamber. Refrigerators of this type are referred to as no-frost refrigerators.

A problem in the construction of these types of refrigerators is the danger of uneven cooling. Refrigerated items placed directly in front of an inlet opening of the cold air coming from the evaporation chamber into the storage chamber will be cooled very efficiently and can screen other refrigerated items from the stream of cold air so that the danger arises of the latter items being cooled insufficiently. If a temperature sensor in the storage chamber is also screened the result can be an incorrect regulation of the temperature; the cooled items directly in the path of the cold air are cooled down too far and may possibly be damaged.

In order to avoid such dangers efforts are generally made to achieve a good spatial distribution of cold air and to feed it at a lower flow speed into the storage chamber by providing a number of inlet openings spaced widely apart or one inlet opening with a large spread in at least one direction for the cold air. In order to distribute the highly concentrated airflow in the area of the fan evenly to the available opening cross-section a known approach is to provide a distribution passage with air guide ribs diverging from each other between the fan and the inlet opening (or the inlet openings) of the air into the storage chamber.

The air guide ribs are only effective however if they do not diverge too far; with guide ribs diverging greatly from one another and correspondingly sharply curved there is the danger of the flow detaching from the surface so that an even distribution of the air cannot be achieved. Also, even if it is possible with the aid of the guide ribs to achieve a satisfactory distribution of the cold air over the entire cross-section of the inlet opening, finding a suitable shape for the guide ribs is a tedious and expensive optimization task.

The object of the present invention is to specify a refrigerator with a storage chamber, an evaporation chamber and a fan for driving an air circulation from the evaporation chamber to the storage chamber, in which an even distribution of the cold air over the cross-section of an inlet opening is able to be achieved in a simple manner and with little optimization effort.

The object is achieved by a grid crossing an elongated inlet opening of the storage chamber. The effect of the grid is two-fold. On the one hand a slight drop in pressure occurs at the grid, which effects an even distribution of the air pressure in front of the grid and thereby an even distribution of the airflow over the entire surface of the grid. On the other hand many individual streams are formed directly downstream from the grid behind its openings which are separated from one another in each case by areas screened by the closed surfaces of the grid. The fact that the many streams each of small cross-section pull air with them from the shielded areas means that they slow down and there is a slow flow obtained over a significantly larger cross-sectional surface than corresponds to the open surface of the grid.

To intensify this carrying-along effect a number of grids can be arranged at the inlet opening in series in air flow terms. In such cases the openings of the grid are preferably offset relative to each other in relation to a surface normal of the grid.

In order on the one hand not to let the drop in pressure at a grid become too great, but on the other hand to have sufficient screened areas between the individual streams, the surface of the grid is preferably between 30 and 60% open.

Because of the use of the grid it is possible to greatly widen out the flow cross section over the short distance between the ventilator and the inlet opening. Thus the distributor passage, the downstream end of which is the inlet opening of the storage chamber, and the greatest cross-sectional dimension of which at its upstream end must be at most half as large as the largest dimension of the inlet opening, must not itself be longer than the largest dimension of the inlet opening itself. This means that even with a very compact form of the refrigerator housing a good distribution of the cold air is achievable.

The length of the distributor passage can even be reduced to two thirds or less of the largest dimension of the inlet opening. Even if the largest cross-sectional dimension at the upstream end of the distributor passage is only a third of the largest dimension of the inlet opening, an even distribution can still be realized.

The refrigerator is easy to assemble if the storage chamber and the distributor passage are delimited by a same inner container and are separated from one another by a partition wall installed in the inner container.

Further features and advantages of the invention emerge from the description given below of exemplary embodiments which refer to the enclosed figures. The figures show:

FIG. 1 a part front view of a carcass of a refrigerator in accordance with the present invention;

FIG. 2 a section through the refrigerator in the depth direction of its housing;

FIG. 3 a section along the plane III-III from FIG. 2; and

FIG. 4 a perspective view of a part of a partition wall between storage chamber and distributor passage of the refrigerator.

FIG. 1 shows a part front view of the carcass of an inventive refrigerator. The carcass 1 has an only partly shown upper and a lower storage chamber 2 or 3 respectively which are separated from one another by a horizontal insulating wall 4. The storage chambers 2, 3 are formed in a manner known per se by deep drawing of a plastic plate into an inner container with a single recess and insertion of the wall 4 into the recess.

Below the wall 4 is located an evaporation chamber 5. It is divided by a housing 7 with a front side suction opening 6 from the lower storage chamber 3.

Behind an opening in the rear wall of the evaporation chamber 5 is located a fan 8 which sucks in air from the evaporation chamber 5. As can be seen in FIG. 3, a cutout 12 is formed in a rear wall insulation layer 11 of the carcass 1, which houses an impeller wheel of the fan 8 and together with the rear wall of the evaporation chamber 5 forms an outflow duct for the air sucked in by the fan 8. A branch 13 of the outflow duct turns into a passage 9 running behind the rear wall of the upper storage chamber 2 and finally emerging into this chamber; another branch emerges in a distributor passage 10 which extends over the entire width of the lower storage chamber 3. The distributor passage is a hollow space of a small depth which is separated from the lower storage chamber 3 by a partition wall 15 injection molded from plastic. The cold air enters into the distributor passage 10 at its upper edge on a cross-sectional surface of 5 to 10 cm wide and a few cm deep; a rear wall of the inner container forming a gap 16 between the lower edge of the partition wall 15 and the rear side of the distributor passage 10 extends over the entire width of the storage chamber 3 of typically appr. 50 cm and has a depth of the order of magnitude of 1 cm.

Two grids 17, which are shown more precisely in the perspective view of FIG. 4, extend over the entire cross-sectional surface of the gap 16. FIG. 4 shows a perspective view of a part of the partition wall 15. The partition wall 15 comprises a wall plate 18 of approximately 50 cm in width, corresponding to the width of the storage chamber 3, and a height of approximately 20 to 30 cm, two webs 19 formed on the vertical edges of the wall plate 18 of which only one is shown in FIG. 4, spacers 20 with an aerodynamic cross-section which are used for anchoring, with the aid of screws for example, the partition wall 15 in the inner container, as well as, distributed along the lower edge of the wall plate 18, a plurality of short ribs which are each divided up by slots 22 into a number of sections. The strip-shaped grids 17 are inserted into the slots 22 in each case. The grids can themselves the rigid elements made of metal or plastic or they can also involve, as shown in the figure, flexible bands made of plastic or fabric, which example are wound at their ends around keder rails to prevent them slipping out of the slots 22.

Openings not shown in the figure each make up around 60% of the surface of the grids 17. The air flows through these openings in parallel to the surface normal of the grid 17. The openings of the grids are offset from each other so that an air stream formed at an opening of the grid 17 lying upstream in each case hits close to the surface of the downstream grid 17 and is broken up by this.

In the diagram shown in FIG. 4 the ribs 21 each have two slots so that two grids 17 can be installed. Naturally the number of slots can also be greater or smaller, with not every slot having to be occupied by a grid. In order not to unnecessarily increase the flow resistance of the distributor passage, in practice only as many grids 17 are installed as are necessary in order to obtain a slow airflow distributed evenly over the entire width of the storage chamber 3 at the output of the distributor passage 10.

As can be seen in the section depicted in FIG. 2, the gap runs horizontally and the air exiting from it is diverted at a horizontal floor surface 24 of the storage chamber 3. Naturally the air could also arrive in the storage chamber via a vertical opening in the wall plate 18. The arrangement shown in FIG. 2 is however preferred since it protects the grid 17 against damage and the diversion of the air streams formed at the openings of the lowest grid 17 contributes to breaking these up and obtaining a slow, homogeneous flow over a large cross-sectional area in the storage chamber 3. 

1-10. (canceled)
 11. A refrigerator, comprising: at least one storage chamber; an evaporation chamber; a fan structured to drive air circulation from the evaporation chamber to the storage chamber; and one or more grids disposed to cross an elongated inlet opening of the storage chamber.
 12. The refrigerator as claimed in claim 11, wherein two or more grids are arranged in series at the elongated inlet opening.
 13. The refrigerator as claimed in claim 12, wherein openings of the two or more grids are offset from one another in relation to a surface normal of the one or more grids.
 14. The refrigerator as claimed in claim 11, wherein a surface of the one or more grids is 30%-60% open.
 15. The refrigerator as claimed claim 11, wherein the elongated inlet opening of the storage chamber extends over an entire width of the storage chamber.
 16. The refrigerator as claimed claim 11, wherein the elongated inlet opening of the storage chamber is a downstream end of a distributor passage, of which a length is smaller than a largest dimension of the elongated inlet opening, and wherein a largest cross-sectional dimension at an upstream end of the distributor passage is at most half as large as the largest dimension of the elongated inlet opening.
 17. The refrigerator as claimed in claim 16, wherein the length of the distributor passage is smaller than two thirds of the largest dimension of the elongated inlet opening.
 18. The refrigerator as claimed in claim 16, wherein in a largest cross-sectional dimension at a downstream end of the distributor passage is at most a third of the largest dimension of the elongated inlet opening.
 19. The refrigerator as claimed in claim 11, further comprising a distributor passage, and wherein the storage chamber and the distributor passage are delimited by a same inner container and are separated from each other by a partition wall installed in the inner container.
 20. The refrigerator as claimed in claim 11, wherein the elongated inlet opening is oriented horizontally. 